1. Field of the Invention
The present invention relates to data storage technology, and particularly to devices implementing magnetoresistive read heads.
2. Background of the Invention
In the data storage field, information is stored in many ways. One way includes writing data onto a magnetic tape by selectively magnetizing regions of the tape. The magnetized tape regions produce a magnetic stray field which can be read by a read head located above the tape surface and converted into an electrical signal. A common type of read head for this task is the magnetoresistive (MR) read head.
A common goal in the information storage industry is to magnetically stabilize a magnetoresistive read head such that the generated electric signal is well behaved. This is frequently accomplished by controlling the boundary or end magnetic domains in a MR element. The control is via magnetic exchange tabs or permanent magnets (PM) deposited at the ends of the element. However, the wider the track width is made, the less effective boundary magnetic control is for the center of the element. A recent technique to overcome this limitation is to introduce a periodic perturbation (gratings) of the element shape in the middle of the device which creates a periodic magnetic charge that stabilizes the middle of the MR element. However, the periodic perturbation can interfere with the magnetic field of the PM and bias current flow direction into MR element. This problem is exacerbated by the fact that read elements must continue to decrease in size to keep up with the scaling of other related technologies. As the read heads are made smaller, the relative sizes of regions of magnetization instability in the MR element grow.
The technology of MR read heads would therefore benefit from a way to stabilize magnetization patterns in the read head.